Safety-valve for air-brake apparatus.



I APPLICATION FILED MAR.7. 1914.

J. W. BINGLEY.

SAFETY VALVE FOR AIR BRAKE APPARATUS.

Patnted Jan. 5, 1915.

ninrrnn snares PATENT ension.

JOHN w. BINGLEY, or WATERTOWN, lvnw YORK, AssIeNon T0 NE YQRK- AIR BRAKE COMPANY, A CORRORATION or NEW JERSEY.

SAFETY-VALVE rennin-BRAKE APPARATUS.

Specification of Letters Patent.

Patented Jan. 5, 11.915.

Application filed March 7, 1914. Serial No. 823,049.

To all whom it may concern:

Be it known that I, JOHN W. BINGLEY, a citizen of the United States, residing in Watertown, in the county of Jefferson and State of New York, have invented an Improvement in Safety-Valves for Air-Brake Apparatus, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to a safety valve or relief valve suitable for use inconnection with the brake cylinder of an air brake apparatus for preventing excessive pressure in thebrake cylinder such as might result in the locking of the car wheels and wearing fiat surfaces thereon.

Owing to the variations in the travel of the piston in the brake cylinder of an air brake'apparatus andv for other reasons there is liability of a greater pressure being produced in the brake cylinder than the maximum under which the brakes are designed to operate in making service applications and this may result in the locking of the wheels on some of the cars of the train and the wearing of flat surfaces on the wheel treads which is highlyobjectionable.

Modern air brake equlpments are in some cases provided with relief valves for pre-- venting such excess of pressure in the brake cylinders and the present invention consists mainly in certain features of construction of such a relief valve by which the valve is caused to open promptly and with ample capacity when the pressure rises to the point which is not to be exceeded, and said valve remains open until the pressure has fallen materially below that whichcaused its opening, and thereupon is closed promptly and tightly.

Figure 1 is a longitudinal section of a reliefvalve embodying the invention in its normal or closed position; Fig. 2 is an enlarged section of a portion of said valve with the valve proper in opened or unseated position;' and Fig. 3 is a sectional detail showing a modified construction.

The base or seat piece .2 is adapted to be connected with the space containing the pressure to be controlled, and-is shown as having a screw threaded neck 3 for attachment to the piping or to any suitable part of the wall of the chamber or space containmg the pressure to be controlled. Said base piece 2 also contains the discharge passage 4 terminating in a valve seat 5which cooperates with the valve proper 6 which has a grooved guide stem working in the passage l. The said Valve is normally held seated by the force of the spring 7 one end of which engages a shoulder or flange on a stem 8 the lower end of which is made conical and has a central bearing upon the valve 6. The said spring 7 is contained in a spring chamher 9 rigidly secured to the base 2 and serv- 1ng to support or connect with the said base the spring abutment 10 which is connected with the upper end of the spring chamber 9 by a screw thread so that it may be adjusted toward or from the base piece to vary the force of the spring 7 and thus determine the pressure required in the passage 4 to lift or unseat the valve. A cap nut 12 which screws on to the spring adjusting nut 10 serves as a lock nut to prevent derangement of the adjustment and also to inclose and make a finish for the parts projecting from the spring chamber. 7

As shown in Fig. 1 the springadjusting nut 10 has adjustably mounted therein a stop '13 for the valve holding stem 8 which stop thus positively and definitely-limits the rise of the valve when unseated by the-action of a pressure in the passage 4 sufiicient to overcome the force of the spring 7.

In the modification shown in Fig. 3 the stop 130 for the valve stem 8 is made integral with the cap nut 12 and is not adjust- .able. In this construction it will be seen that the change of position of the spring nut 10 for adjusting the force of the spring 7 does not vary the position of the stop 130 relative to the stem 8 so that said stop atfords the same limit for the rise of the valve with all adjustments of the spring pressure.

The valve 6 has an outwardly extended flange or enlargement surrounding the portion that engages the seat, and the base piece 2 containing the valve seat has a depression surrounding the seat and contaming the valve enlargement 60 when the valve is seated. The floor 61 of said depression lies beneath the enlargement 60 of the valve 6 as best shown in 1, and said enlargement of the valve affords an additional area subjected to the pressure of the escaping fluid when the pressure in the passage 4: is suflicient to lift the valve 6 from its seat, thus giving an increase in lifting pressure over that which is suflicient to unseat the valve and thus serving to move the valve promptly and somewhat extensively against the pressure of the spring 7 as is well understood, such additional valve lifting force being exhibited in the operation of the well known pop safety valves.

In the present construction the side wall of the recess around the valve seat is made higher than the thickness of the enlargement 60 of the valve, and is tapered as shown at 62, being smaller at the end remote from the floor 61 than where the said wall intersects the said floor of the cavity surrounding the valve seat.

The outer periphery of the enlargement 60 of the valve is correspondingly-tapered as shown at 63 and is preferably of such size that the largest part of the periphery of the valve will just pass through the opening at the top of the cavity in the valve seat.

By this construction it will be seen that an annular passage is afforded for the escape of the fluid between the periphery 63 of the enlargement of the valve and the side wall 62 of the cavity around the valve seat, and that the efiective area of this annular opening decreases as the valve rises and would be practically closed if the valve were permitted to rise until the lower end of its enlargement coincided with the upper end of the side wall of the cavity. The amount of this upward movement of the valve is determined by locating or adjusting thestop 130 or 13 to arrest the valve in its rising or opening movement at any desired point, with the lower edge of the enlargement 60 below the upper edge of the side wall 62, and the annular discharge opening between the tapered surfaces 62, 63, may thus be made of any desired width and effective area and may therefore be made to restrict the discharge of the fluid more or less and thereby to retain more or less pressure in the cavity surrounding the valve seat under the enlargement of the valve in addition to that in the passage 4, so that the valve may be held unseated until the pressure has been lowered the desired amount below that which is suflicient to unseat the valve. As soon, however, as the total pressure under the valve and its enlargement becomes insufficient to overcome the force of the spring 7 the latter begins to move the valve toward its seat and in so doing enlarges the annular opening between the surfaces 62, 63, and thereby efiects a reduction of the pressure in the recess below the enlargement of the valve so that the spring, notwithstanding the fact that it is expanding and losing force in this movement of the valve toward its seat promptly overcomes the opposing fiuid pressure and causes the valve to close promptly and seat tightly as soon as the desired reduction in pressure has been obtained.

The spring chamber has one or more discharge openings 65 of proper capacity to discharge the fluid after it has passed the valve without causing objectionable pressure to be produced in the spring chamber over the valve.

What I claim is:

1. The combination of the valve seat, valve, and means for yieldingly holding the valve pressed to its seat, said valve being provided with an enlargement around its seating portion affording an additional area adapted to be exposed tofluid pressure when the valve 1s unseated and the valve seat being provided with a recess containing said en argement; the walls of said enlargement and recess bein convergent in the direction of movement 0% the valve in unseating and thereby afl'ording a passage between them the eflective area of which is reduced as the distance to which the valve is moved from its seat increases substantially as described.

2. The combination of the valve seat, valve, and means for yieldingly holding the valve pressed to its seat, said valve being provided with an enlargement around its seating portion afi'ording an additional area adapted to be exposed to fluid pressure when the valve is unseated and the valve seat being provided with a recess containing said enlargement; the walls of said enlargement and recess -being convergent in the direction of movement of the valve in unseating and thereby afl ording a passage the efiective area of which is reduced as the distance to which the valve is moved from its seat increases, and a stop for determining the distance to which the valve is moved when unseated by fluid pressure.

3. The combination of the base provided with a discharge passage; a valve'seat; and a recess around said valve seat, with a valve cooperating with said valve seat and having an enlargement contained in the said recess thereof afiordin an additional area adapted to be expose to fluid pressure when the valve is unseated, said enlargement of the valve and recess in the valve seat being convergent in the direction of movement of the valve in unseating as described; a stem engaging said valve and a spring chamber connected with said base and spring abutment adjustably connected with said spring mee eoe chamber, and a spring inter osed between ,name to this specification in the presence of said sprilg abutment and sai valve hglding two subscribing witnesses. stem, an a, stop cooperating with sai stem for limiting the movement of the valve from JOHN BINGLEY' 5 its seat, substantially as and for the pur- Witnesses:

pose described. WM. EDWARDS, In testimony whereof, I have signed my HAZEL Hymns. 

